Unconventional ferromagnetism and transport properties of (In,Mn)Sb dilute magnetic semiconductor

Abstract

Narrow-gap higher mobility semiconducting alloys In 1−x Mn x Sb were synthesized in polycrystalline form and their magnetic and transport properties have been investigated. Ferromagnetic response in In 0.98 Mn 0.02 Sb was detected by the observation of clear hysteresis loops up to room temperature in direct magnetization measurements. An unconventional (reentrant) magnetization versus temperature behavior has been found. We explained the observed peculiarities within the frameworks of recent models which suggest that a strong temperature dependence of the carrier density is a crucial parameter determining carrier-mediated ferromagnetism of (III,Mn)V semiconductors. The correlation between magnetic states and transport properties of the sample has been discussed. The contact spectroscopy method is used to investigate a band structure of (InMn)Sb near the Fermi level. Measurements of the degree of charge current spin polarization have been carried out using the point contact Andreev reflection (AR) spectroscopy. The AR data are analyzed by introducing a quasiparticle spectrum broadening, which is likely to be related to magnetic scattering in the contact. The AR spectroscopy data argued that at low temperature the sample is decomposed on metallic ferromagnetic clusters with relatively high spin polarization of charge carriers (up to 65% at 4.2K) within a cluster.

Simplest model to study reentrance in physical systems

“…For example, Rochelle salt was found to be a ferroelectric with two Curie points; the ordered ferroelectric phase occurs only between these two temperatures [1]. More recently, similar phase diagrams have been seen for superconducting vortices [2,3], liquid crystals [4], miscibility in solutions [5], polymeric materials [6], ferromagnetism in semiconductors [7], denaturation of DNA [8], and many other systems [9,10].…”

Controlling the growth morphology and phase segregation of Mn-doped Ga2Se3on Si(001)

“…MnGa 2 Se 4 is antiferromagnetic with a Nèel temperature of 8 K. 13 The MnSe case is more complicated; structural transitions occur simultaneously with magnetic transitions to antiferromagnetism between 90 and 300 K. 14 The magnetism in Mn-doped layered GaSe exhibits an unusual temperature dependence where the magnetization increases with increasing temperature between 100 K and 170 K. 15 This is very interesting due to the possibility of a reentrant carrier-mediated ferromagnetic semiconductor, which becomes ferromagnetic as temperature is increased due the increase in free carrier density as predicted in [16] and reported experimentally in [17]. Meanwhile, nothing is known about the magnetic behavior of Mn-doped Ga 2 Se 3 .…”

Room-Temperature Ferromagnetism in InSb-Mn Nanowires

“…Indium antimonide (semiconductor with a large Bohr radius, excellent electron mobility, up to 7.8 m 2 V –1 s –1 and a small band gap = 0.17 eV) doped with manganese atoms is considered a promising platform to realize room-temperature ferromagnetism/ferrimagnetism in narrow gap semiconducting systems. , Due to the very low equilibrium solubility of Mn in III–V semiconductors, it is difficult to incorporate these magnetic atoms into the host material at high concentrations. In most cases, the doping is realized by dislocation in the semiconductor lattice, which deteriorate the mechanical, magnetic, , and electrical , properties of crystals. However, for the Curie temperature ( T C ) to be increased to room temperature, an appreciably high concentration of the 3d element is required, which often results in the formation of clusters.…”

“…2,3 Due to the very low equilibrium solubility of Mn in III−V semiconductors, it is difficult to incorporate these magnetic atoms into the host material at high concentrations. In most cases, the doping is realized by dislocation in the semiconductor lattice, which deteriorate the mechanical, 4 magnetic, 5,6 and electrical 7,8 properties of crystals. However, for the Curie temperature (T C ) to be increased to room temperature, an appreciably high concentration of the 3d element is required, which often results in the formation of clusters.…”